Long-term associations of outdoor air pollution with mortality in Great Britain

Abstract

Background: Recent studies have indicated long-term effects on mortality of particulate and sulphur dioxide (SO 2 ) pollution, but uncertainties remain over the size of any effects, potential latency and generalisability. Methods: A small area study was performed across electoral wards in Great Britain of mean annual black smoke (BS) and SO 2 concentrations (from 1966) and subsequent all-cause and cause-specific mortality using random effect models within a Bayesian framework adjusted for social deprivation and urban/rural classification. Different latencies and changes in associations over time were assessed. Results: Significant associations were found between BS and SO 2 concentrations and mortality. The effects were stronger for respiratory illness than other causes of mortality for the most recent exposure periods (shorter latency times) and most recent mortality period (lower pollutant concentrations). In pooled analysis across four sequential 4 year mortality periods , adjusted excess relative risk for respiratory mortality was 3.6% (95% CI 2.6% to 4.5%) per 10 mg/m 3 BS and 13.2% (95% CI 11.5% to 14.9%) per 10 ppb SO 2 , and in the most recent period (1994-8) it was 19.3% (95% CI 5.1% to 35.7%) and 21.7% (95% CI 2.9% to 38.5%), respectively. Conclusions: These findings add to the evidence that air pollution has long-term effects on mortality and point to continuing public health risks even at the relatively lower levels of BS and SO 2 that now occur. They therefore have importance for policies on public health protection through regulation and control of air pollution.

Mortality Associations with Long-Term Exposure to Outdoor Air Pollution in a National English Cohort

“…Elsewhere, population studies in Norway (13), Japan (18), New Zealand (17), and China (38) have all reported statistically significant, positive associations with respiratory mortality. In the United Kingdom, a national ecologic study (39) reported larger effects of black smoke (a reflectance measure of black carbon particles ,4 mm in diameter) on respiratory mortality (HR, 1.19) in the most recent exposure periods (1990-1994), whereas a Scottish study (40) also found larger relationships with respiratory mortality (HR, 1.26). Our scaled findings for PM 10 and PM 2.5 (HR, 1.30 and 1.54, respectively, per 10 mg/m 3 ) adjusted for area income deprivation exceed all but one (38) of the reported estimates in Table 5; however, we note the smaller mean and standard deviation of our modeled concentrations compared with other studies.…”

Long-Term Ambient Multipollutant Exposures and Mortality

“…Most long-term studies haven't reported elevated risks (9,15,18,37) with all-cause mortality. Positive effects have been observed in a study in Great Britain (39), in a recent reanalysis of the American Cancer Society cohort (40), and in many short-term studies with cardiovascular deaths and/ or hospital admissions (41).…”

Impact of Air Pollution on Public Health

“…Significant associations were found between black smoke (BS) and SO 2 concentrations and mortality. The effects were stronger for respiratory illness than other causes of mortality for the most recent exposure periods (shorter latency times) and most recent mortality period (lower pollutant concentrations) [30]. Air pollution has long-term effects on mortality and point to continuing public health risks.…”

“…Air pollution has long-term effects on mortality and point to continuing public health risks. They therefore have importance for policies on public health protection through regulation and control of air pollution [30].…”